Demographic Predictors of Treatment and Complications in Adult Spinal Deformity: An Analysis of 17,433 Patients Using the National Inpatient Sample

Introduction: To examine the role of demographics on surgical management and inpatient complications in patients with spinal deformity between 2010 and 2014 via retrospective analysis of national administrative hospital data.

Methods: Data were obtained from the National Inpatient Sample (NIS). International Classification of Diseases 9th revision (ICD-9-CM) codes were used to identify patients with a primary diagnosis of adult spinal deformity (ASD). Multivariate Poisson regression analyses were used to determine whether any individual demographic variable such as sex, race, insurance type, region, and hospital type were predictive of surgical management, surgical complexity, postoperative complications and revision operations.

Results: A total of 17,433 patients were identified for analysis. Overall, we observed a rate of surgical intervention of 94.5% for patients with a primary diagnosis of ASD. Patients at urban teaching hospitals were the most likely to receive surgery (OR= 2.13; 95% CI 1.51-2.95; p< 0.001) relative to rural patients. Female patients represented the majority of surgical cases, and were more likely to receive a complication or require a revision when controlling for surgical complexity. Interestingly, Medicare patients, who were the least likely to be operated on and the most likely to receive complex fusion when operated on, were the least likely to experience complications (OR=0.89; 95% CI 0.80-0.98; p=0.022) after adjusting for surgical complexity. With regards to race, Hispanics had a decreased likelihood of receiving a revision surgery.

Conclusion : There were substantial differences in rates of surgical management, postoperative complications, and revisions among individuals of different demographics including sex, insurance status, race and hospital teaching status. Further research evaluating the effect of demographics in spine surgery is warranted to fully understand their influence on patient outcomes.